1. Field of the Invention
The present invention relates to a burner for a gas-cooker with an interchangeable circumferential ring i.e. a burner in which the base ring can be replaced to adapt it to the requirements of the cooking hob on which it is fitted.
Gas burners for domestic use generally comprise a base element, comprising the gas injector, and the body of the burner, resting on the base element and forming a Venturi to mix the gas with the primary air, together with passages for the mixture up to the openings of the flame exits.
The primary air can be fed from under the cooking hob or (preferentially in the case of cooking hobs separated from the main body of the economic cooker) from above the cooking hob.
In the first case, the burner doesn't require any external element to convey the primary air and therefore the burner can have an essentially cylindrical external configuration with a vertical axis. An embodiment is known in which the cylindrical burner is surrounded by a sheet metal ring, generally curved in shape, which rests freely on the hob, has an ornamental function and can also help to prevent liquid from penetrating into the lower part of the cooker. As described, this ring is simply resting on the hob and therefore its axial and radial position with respect to the burner is always very approximate and unstable. In gas burners which collect the primary air from above the cooking hob, it is, however, necessary to convey the air toward the interior of the burner and an external circumferential ring is therefore provided, pressed as one piece with the body of the burner, which stretches toward the lower part in the direction of the cooking hob and forms with the latter, when the burner is fitted, a circumferential passage which admits the required primary air. This one-piece external ring, while fulfilling its own function effectively, has the disadvantage of constituting an aesthetically anomalous element on the cooking hob, which is generally enameled and colored, as the upper covers of the burners are also enameled and colored.
2. Objects of the Invention
Based on the above premises, it is now the principal purpose of the present invention to provide a burner with an external ring which can easily be adjusted to the aesthetic requirements of the different cooking hobs.
In the case of burners which collect air from above the cooking hob, the purpose of the invention is to provide a burner with external ring which adjusts to the aesthetic requirements of the different cooking hobs while always maintaining its own exactly defined functional characteristics, with the surface of the cooking hob, and a circumferential passage for the entry of the primary air toward the interior of the burner.